Abstract:

Significance Perceptive deformable smart materials, inspired by soft organisms, exhibit adaptive deformability and safety interaction superiorities. They can monitor and feedback environmental information or facilitate self-detection in real time, showing important application potentials in smart equipment, industrial production, daily life, environment and biomedicine, and so on. Flexible fibers possess high specific surface area and morphological superiority, which can be transformed into yarns, loops, and fabrics through textile processes, demonstrating high designability in structure, functions, mechanical properties and deformation capabilities, making them an ideal candidate for creating smart deformable materials. In recent years, tremendous efforts have been dedicated to the exploitation of fiber-based smart deformable materials. In particular, perceptive deformation fiber materials have attracted much research attention, promising the integration of deformation and sensing promoting the development of smart material in the fields of wearables, e-skins, soft robotics, military and aerospace.
Progress In recent years, substantial progress has been achieved in the research of smart deformable fiber materials. These materials can respond to various environmental stimuli, such as humidity, heat, light, electricity, magnetism, and air pressure, thereby triggering actuations like contraction, expansion, bending, and rotation, and they are widely applied in multiple fields. In terms of actuation mechanisms, electrical actuation has gained considerable attention by virtue of its high controllability and rapid response. The carbon nanotube/polyaniline fiber actuator can operate in aqueous electrolytes at a low voltage of 2 V, demonstrating significant potential for use in implantable artificial muscles. Moisture actuation utilizes the hygroscopic properties of materials to achieve actuation. Light actuation relies on photothermal or photochemical effects to enable rapid and reversible deformations. The double-layered fiber membrane enables bidirectional bending in response to both light and humidity, exhibiting an ultrafast response rate and a substantial bending curvature. Magnetic actuation materials integrate magnetic particles or fibers, which enable complex deformations under magnetic fields.The magnetic coaxial fibers exhibit multifunctional motions, including crawling, walking, and swimming, when exposed to magnetic fields. Pneumatic actuation relies on external air pressure. The knitted pneumatic actuator can achieve complex movements with precise control. In terms of actuation-sensing integration, fiber actuators with integrated sensing functions can monitor environmental or self-states, thereby promoting the development of artificial muscles and soft robots. Furthermore, origami techniques have provided novel ideas for the design and functional expansion of actuators.
Conclusion and Prospect Although certain achievements have been made in the research on perceptive deformable fiber/fabric materials, challenges remain in improving the response performance, stability/reliability, and application feasibility of the materials. Firstly, it is necessary to further explore and gain an in-depth understanding of actuation mechanisms, clarify the relationship between the micro and macro deformation performance of materials, and leverage simulation and machine learning technologies to improve macro deformation performance. Secondly, it is essential to enhance the deformation performance and long-term stability of materials through material and structural innovations, as well as intelligent encapsulation technologies, so as to improve their reliability in harsh environments. Finally, facilitating module/function integration and large-scale manufacturing by weaving high performance fibers/yarns with textile engineering technologies would be a promising solution to address these concerns and advance the field of intelligent deformable materials. In the future, fiber/fabric based smart deformation materials are expected to be widely used in responsive smart devices and equipment, serving applications in soft robotics, wearables, rehabilitation assistance, bio-health, military equipment, aerospace, smart industry, and smart agriculture, among other fields.

Key words: smart deformable material, fiber, yarn, fabric, actuation-sensing integration, actuator, soft robot